Device for charging alloyed iron and secondary raw materials into a steelmaking furnace



Apri 1959' KOICHI TAGIRI TAL I 3,435,98

v DEVICE FUR CHARGING ALLQYED IRON-AND SECONDARY RAW MATERIALS INTO A STEELMAKING FURNACE FIGS}. 1

Filed July 18, 1966 Ko lchi Tagiri *Masuo Iwai 7- t I J Yoshi waka Ni kaido United States Patent U.S. Cl. 214-35 1 Claim ABSTRACT OF THE DISCLOSURE A charging shoot device for charging secondary raw materials and alloyed irons into a steelmaking furnace. The device has an outer pipe adapted to be mounted on a furnace hood, to which is connected a feed pipe for supplying the materials to be added. An inner pipe is slidable in the outer pipe and has a lateral opening which in one position is in register with the feed pipe Opening, and in the other position is out of register therewith. The end of the inner pipe which is toward the hood has an acute-angled cutting edge thereon which is slidable along the inside surface of the outer pipe in order to scrap off accumulated molten metal or slag which splashes up from the molten bath.

The present invention relates to a device for charging alloyed iron and secondary raw materials into a steelmaking furnace.

In general, during the operation of a steelmaking furnace such as a converter, secondary raw materials, such as, calcium oxide, scales, fluorite and the like and alloyed irons, such as, Fe-Mn and Fe-Si are charged into the furnace for adjusting the composition of the molten steel therein. The charging is generally conducted by means of a shoot. However, when employing a shoot, the splashes of the molten steel or slags in the furnace caused by oxygen blowing are stuck to the inside wall of the shoot and accumulated there gradually to narrow the passage of the shoot. Consequently, the charging of the secondary raw materials or the alloyed irons will not be con ducted smoothly and, as the case may be, charging has to be stopped.

Further, the use of the charging shoot is frequently accompanied by the phenomenon of backfire from the converter, which results in discharging of harmful gases such as CO through the shoot into workrooms. Therefore, since the working environment is poisoned, the operation will be accompanied by great dangers.

In order to overcome these drawbacks it has been proposed to provide gas jet pipes at a suitable portion of the charging shoot, through which a high pressure gas is jetted into the opening of the converter to provide a gas seal. However, although such a means may give a satisfactory result by preventing the occurrence of backfire, there is the drawback that a compressor for gas for the jetting and the like must be provided in addition to the usual equipment.

An object of this invention is to provide a device for charging alloyed irons and secondary raw materials while preventing the accumulation of molten steel or molten slag at the outlet end of the charging shoot.

Other object of this invention is to provide a device for charging alloyed irons or secondary raw materials while preventing the occurrence of backfire in the charging shoot.

These objects are achieved by the charging shoot device according to the present invention. The device has an outer pipe adapted to be mounted on a furnace hood,

3,435,968 Patented Apr. 1, 1969 to which is connected a feed pipe for supplying the materials to be added. An inner pipe is slidable in the outer pipe and has a lateral opening which in one position is in register with the feed pipe opening, and in the other position is out of register therewith. The end of the inner pipe which is toward the hood has an acute-angled cutting edge thereon which is slidable along the inside surface of the outer pipe in order to scrape off accumulated molten metal or slag which splashes up from the molten bath.

Further objects of the present invention will become apparent from the following descriptions and the accompanying drawings, in which FIG. 1 is an elevation view, partly in section, of one embodiment of this invention showing the charging shoot being lifted up, during which secondary raw materials or alloyed irons are not being charged,

FIG. 2 is a schematic view showing a part of the charging shoot of this invention, and

FIG. 3 is a view similar to FIG. 1, showing, however, the position of the charging shoot when the secondary raw materials or alloyed irons are being charged therethrough.

As is clear from the above figures, according to the present invention, a pipe for supplying secondary raw materials and alloyed irons is connected with an outer pipe of the charging shoot, and an inner pipe of the charging shoot, which has an opening the same size as the communicating opening of the said charging pipe, is positioned slidably in said outer pipe.

The shoot system of the present invention may be applied to any known steelmaking furnaces but the invention will be explained in detail and practically by referring to the figures which shows the application of the invention to a converter.

In the figures, above a converter 1 is provided a converter hood 2. Connected to the hood 2 is an outer pipe 8 of the charging shoot having at its forward part a cooling jacket 3, and connected near the middle portion of the outer pipe 8 is a pipe 5 for supplying secondary raw materials and alloyed irons. The cooling jacket 3 is not always necessary and an elongated outer pipe may of course be employed in place thereof. There is an opening 12 in the portion of the outer pipe 8 where the supply pipe 5 is connected with the outer pipe 8. In the outer pipe 8 is slidably positioned an inner pipe of the charging shoot having an opening 10 which can be positioned so as to be in register with the opening 12 of the outer pipe 8 by the sliding motion of the inner pipe. The top of the inner pipe 6 of the charging shoot is fixed to a moving means 7 and the inner pipe 6 can be caused to slide vertically along the inside wall of the outer pipe 8 by means of the moving means 7. In the figures there is illustrated an oil-pressure cylinder which constitutes the moving means 7 which is also rigidly mounted on the pipe 5 for supplying raw materials. However, it will be understood easily that the moving means can be mounted on any other convenient member. The forward end of the inner pipe 6 of the charging shoot may be provided with a bevel 11 of a suitable acute angle. Further, if necessary, a seal packing 9 may be positioned between the outer pipe 8 and the inner pipe 6, to facilitate the sliding motion.

In the above-mentioned device of this invention, the inner pipe 6 of the charging shoot is in a raised position as shown in FIG. 1 when secondary raw materials and alloyed irons are not charged in the furnace. Since in this case the opening 10 of the inner pipe 6 of the charging shoot is not in register with the opening 12 of the outer pipe 8, that is, the opening 12 of the outer pipe is closed by the wall of the inner pipe 6, the occurrence of backfire from the furnace can be prevented. In order to charge secondary raw materials and alloyed irons, the inner pipe 6 of the charging shoot is moved down by the action of the moving means 7 to bring the open ing 10 of the inner pipe into register with the opening 12 of the outer pipe, whereby the secondary raw materials and alloyed irons can be charged into the furnace through the pipe 5. In this case, even if the splashes 4 of the molten metal or slag from the furnace should stick to the inside wall of the cooling jacket, they are stripped off the wall when the inner pipe of the charging shoot is moved down. It is preferable, in this case, for stripping off the stuck metal or slag that the forward end 11 of the inner pipe be formed into an acute-angled cut.

Thus, the device according to the present invention has very valuable practical effects, because it is so designed that by vertically sliding the inner pipe of the charging shoot the occurrence of backfire from the furnace may be prevented and at the same time the accumulation of the splashes of molten metal or slag may be prevented.

What is claimed is:

1. A charging shoot device for charging secondary raw materials and alloyed irons into a steelmaking furnace, comprising an outer pipe adapted to be mounted on a furnace hood, a feed pipe for supplying materials and connected to and opening into said outer pipe, and an inner pipe having a lateral opening therein, said inner pipe being slidable in said outer pipe from a position in which said opening is in register with said feed pipe opening and the end of said inner pipe toward the hood connected end of said outer pipe extends at least substantially to a position in register with said hood connected end of said outer pipe to a position in which said opening is out of register with said feed pipe opening, the end of said inner pipe toward said hood connected end of said pipe being beveled to form an acuteangled cutting edge slidable along the inside surface of said outer pipe.

References Cited UNITED STATES PATENTS 2,004,533 6/1935 Maynard.

ROBERT G. SHERIDAN, Primary Examiner. 

